1. Field of the Invention
This invention relates to an automatic production line control data forming system in which, in production control (production line scheduling) of a production line equipped with machine tools and industrial robots, or in an automatic programing system for production machines such as machine tools and industrial robots, a computer reuses data on the results of processing provided by a process designing system or data on the results of intermediate processing, thereby to form at least one day's schedule plans and NC (numerical control) automatic programs with high efficiency.
2. Prior Art
FIG. 6 is a diagram showing the arrangement of a conventional production system. In FIG. 6, reference numeral 10 designates a process planning system for determining the order of use of production machines, jigs and tools according to drawings provided for parts to be manufactured; 50, a production machine file which is referred to for process planning; 19, a process and work know-how file for determining the order of processes or operations; 20, a production line scheduling system for forming at least one day's schedule plans according to an article producing plan; 28, a machining time file in which the machining time for each of the machining processes provided for parts to be manufactured is stored; and 29, a scheduling know-how file in which know-how as to the schedule plans for each of the days are stored.
Further in FIG. 6, reference numeral 60 designates a production instruction manual revealing the contents of machining, assembling and preparing operations which are finally determined according to process plans and the schedule plans for each of the days; 30, a production preparation supporting system for preparing concrete production data, the system 30 comprising an NC (numerical control) automatic programming system for supporting the formation of NC programs, an automatic programming system for supporting the formation of robot control programs, and an arrangement system for supporting the preparation of materials, jigs, etc.; and 40, a production line on which parts are machined and assembled. The production line 40 is made up of machining cells 41 and 42 including mainly machine tools, and an assembling cell 43 including mainly robots and assembling machines.
The production line shown in FIG. 6 is of a large scale, and its operation is considerably intricate. Hereunder, the functions and operations of the production line will be described with reference mainly to machining operations. Upon completion of an article designing operation, article data such as drawings are handed to the manufacture department, where responsible persons in an article designing section, in a production planning section, and in a production control section hold meetings to study articles to be manufactured, and the delivery dates and the number of the articles, and have discussions about problems which may be involved in process planning, production control, and manufacturing, thereby to roughly determine production activities such as procurement of materials and countermeasures against bottle-neck problems.
Thereafter, the production data are gradually detailed as follows. First, a process planner performs a process planning operation by using the process planning system 10 according to given part drawings, to select production machines to be used for manufacture of the parts, and determine the order in which the selected machines are to be used, and also to select mounting appliances and tools and determine the order in which the selected mounting appliances and tools are to be used. If, in this case, the same part has been manufactured before, then the process planner refers to the processes previously employed for that part. Furthermore, in determination of the processes, reference is made to the production machine file 50 and the process and work know-how file 19. The process planner considers, according to the part drawings provided by the designer, the configurations of intermediate parts which should be formed to reach the aimed part, and makes so-called "machining drawings" for the intermediate parts. The machining drawings include data on preparing operations and machining operations in all the machining processes. The above-described process planning operation is carried out for each of the parts of the article.
Next, the production controller, while taking the kinds of parts to be manufactured, the number of each of the parts and the delivery data thereof, production machines (such a machine tools and jigs) used to manufacture the parts determined by the planning of processes, and periods of time required for the manufacturing processes (such as machining, conveying and assembling processes) into account, makes a rough plan for every one or six months, and uses the production scheduling system 20 to perform a scheduling operation, to concretely determine the days' schedule plans for a certain period. In each of the day's schedule plans, as for each of the parts of an article to be manufactured, it is determined who will operate what machine in what machining processes. In this case, reference is made to the machining time file 28 to detect periods of time required for the machining processes, and to the schedule know-how file for elimination of the difficulty that the line balance is poor.
Thus, a document 60 concerning work instructions, assignment of persons, and NC program preparation for machining and assembling operations is formed according to the process plans and the production schedules for a certain period. Production preparations are started in accordance with this production instruction manual. Programs for the NC machine tools, robots, etc. are formed by using a CAM (automatic programming) system 30. As for the materials, mounting appliance and tools, a procedure is taken to procure them if they are not available. These preparatory operations are achieved before the production starts. A work instruction table, assignment of persons, NC programs, etc. which are determined by the process planning operation, scheduling operation, and production preparation are handed to the production line 40 including the machining cells 41 and 42 and the assembling cell 43, to start the production.
In the formation of control data for the conventional production line, the results (or data) of process planning and scheduling operations cannot be reused for other work, and accordingly the frequency of reinputting data is increased, which lowers the productivity. One of the reasons for this; is that the process planning operation, the production scheduling operation, and the production preparation are highly technical, and another is that a number of persons must work sharing manufacturing operations, and therefore the production is partially computer-aided. Furthermore, the transmission of information between organizations in the factory is carried out with documents such as work instruction tables, machining drawings and Gantt charts which are standardized in that factory.
For instance, one of the outputs of the processing planning operation is machining drawings which specify configurations of parts to be formed and portions of the parts to be machined. In the processing planning operation, part drawings are employed as input data; however, those part drawings are not processed by the computer, or, in many cases, they are not used as output data even when they are processed by the computer. Furthermore, the machining drawings are handed, in the form of paper drawings, for a production preparation performed downstream of the production line, and therefore in formation of NC programs, the machining drawings cannot be used as data by the computer, and data may be inputted with error.
Thus, there has been a demand for provision of a system in which, in the initial process planning step of a production activity, a model necessary for the production is defined, and it is converted into data which are required for production control and production preparation according to the intermediate data or results which-are obtained from information inputted, so that the data can be reused.